A Caltech Library Service

A Direct Velocity Measurement Apparatus to Determine the Specific Electronic Charge


Ogier, Walter Thomas (1953) A Direct Velocity Measurement Apparatus to Determine the Specific Electronic Charge. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/WMM8-DH40.


An apparatus for the precision measurement of the charge to mass ratio of the electron by a direct velocity method is described. This apparatus uses a resonant cavity as a velocity selector. A carefully collimated beam of electrons is deflected by the rapidly rotating magnetic field produced across the center of a right circular cylindrical cavity operated in two TH[subscript 110] modes excited in time and space quadrature. Measurement is made of the beam voltages for which the beam receives no net transverse velocity from the cavity field. These voltages correspond to transit times of integral number of cycles in the field. From the cavity length and frequency the electron velocities are calculated, and from these velocities and the corresponding voltages the charge to mass ratio is obtained. Preliminary results are presented indicating that the attainable accuracy with this instrument should be better than one part in ten thousand.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Physics and Mathematics)
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Minor Option:Mathematics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Smythe, William Ralph
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1953
Record Number:CaltechETD:etd-04282003-155015
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1528
Deposited By: Imported from ETD-db
Deposited On:29 Apr 2003
Last Modified:07 Jun 2023 19:32

Thesis Files

PDF (Ogier_wt_1953.pdf) - Final Version
See Usage Policy.


Repository Staff Only: item control page